binutils/testsuite: Support stderr options with `run_dump_test'

binutils/testsuite: Support stderr options with `run_dump_test'

Add support for the `error', `error_output', `warning' and
`warning_output' options for `run_dump_test' input files, based on the
version of the procedure in ld/testsuite/lib/ld-lib.exp and providing
compatible semantics.  These options apply to PROG under test and let
test cases specify output expected on stderr as well as express a
requirement for PROG to exit unsuccessfully.  Messages to match against
can be supplied either inline or fetched from a named file.  Update
procedure description in the introductory comment accordingly.

As the exit status from `remote_exec' is regrettably lost in our default
implementation of `binutils_run', which is user-overridable, avoid
changing this procedure's API and use a global `binutils_run_status'
variable to pass the status up to the caller, similarly to how
`binutils_run_failed' is handled.  Document the new variable in the
respective introductory comments.

	binutils/
	* testsuite/config/default.exp (binutils_run): Document
	`binutils_run_status'.
	* testsuite/lib/utils-lib.exp (default_binutils_run): Likewise,
	and set it.
	(run_dump_test): Add `error', `error_output', `warning' and
	`warning_output' options.  Update documentation accordingly.